package BYD;

/**
 * @author ht
 * @create 2025-06-28 18:25
 * @desc
 **/
public class T3 {

    //计算一个数能由多少个质数构成

    public static void main(String[] args) {
        int n = 10;

        if(n == 1) {
            System.out.println(0);
        }

        if(n == 2) {
            System.out.println(1);
        }

        if( n % 2 == 0) {
            System.out.println(n / 2);
        } else {
            System.out.println((n - 3) / 2 + 1);
        }

    }
}
